1. Technical Field
The present disclosure relates to a vehicle body floor structure. More particularly, the present disclosure relates to a measure tor suppressing vibration occurring in a floor panel.
2. Description of Related Art
As disclosed in Japanese Patent Application Publication No. 2909-286249 (JP 2009-286249 A), a floor panel of a vehicle body has welded thereon vehicle body framework members, such as frames extending along a vehicle body front-rear direction and cross members extending along a vehicle width direction.
When the vehicle body vibrates as a result of an input from a road surface into the vehicle body, transmission of vibration from the engine, etc., and the frequency of this vibration of the vehicle body matches the resonance frequency of the floor panel, the floor panel resonates and generates abnormal noise (low-frequency solid-borne sound), such as booming noise, giving an uncomfortable feeling to an occupant.
It has been proposed to enhance the rigidity of a floor panel as means for suppressing generation of such abnormal noise accompanying resonance of the floor panel. For example, JP 2009-286249 A discloses a structure in which triangular flat surfaces are combined at angles so as to form protrusions on a floor panel. This structure suppresses generation of the abnormal noise by allowing the resonance frequency of the floor panel to be set higher without causing an increase in the plate thickness of the floor panel.
On the other hand, Japanese Patent Application Publication No. 2006-7862 discloses a technique of damping vibration occurring in a floor panel by coating substantially the entire upper surface of the floor panel evenly with a vibration damping material.